Rotary hammer



April 2 1929.

G. E. WAGNER ROTARY HAMMER Filed Jan. 30, 1928 W w 4 m m w f. A M 7 4 S m w r -w .Pv fl. I 7 W v Pmmd A r. 2, 1929.

UNITED STATES PATENT OFFICE.

GEORGE ERNEST WAGNER, OF 8T.-ETIENKE, FRANCE, ASSIGNOB TO SOCIETE ANON- YKE I'B'ANCAISE DITE: BOCIETE ANONYM'E DEXPLOITATION DES BBEVETS GEOBGEVITCH ET WAGEOB POUR DES IARTEAUX BOTAT-II'S KABGEOWA, OF ST.-

ETIENNE, LOIBE FRANCE.

ROTARY Application filed January 89, 1928, Serial Io. 250,888, and in lrancelseptember 24, 1927.

Various kinds of rotary hammers operating by centrifugal force are known, comprising striking masses adapted to describe a rotary path by being carried on a rota frame on the arms of which they slide radially, the rotary frame being actuated by a suitable mechanical transmission. These striking masses, in their'rotar movement, are carried successively towar s the centre of rotation and are then left to themselves at a predetermined point in their travel so that they can strike a tool on the head.

All such hammers and whatever the number of strikin masses in play therein present 1 the serious efect of causlng considerable vibration in the gear case, in consequence of the complete freedom allowed to each of the striking masses, from the moment when they move away from the centre until the moment 2 they strike on the anvil; furthermore, owing to the fact that rigid runways are employed,

shocks are produced which are injurious to the performance of the apparatus and to the preservation of their parts, when the striking masses, after having effected their work on the head of the tool,- resume contact with the runway.

The present invention has for its object improvements in the rotary hammers referred to, these improvements resulting in a considerable lessening of the vibrations and shocks-due to the lack of equilibration pro. duced by the movements of the striking masses and the rigidity of the runways.

. These improvements reside in the form and nature of the runways.

In the accompanying drawings Fig. 1 is a sectional view on the median line of the runway of a hammer constructed in accordance withthe invention;

Fig. 2 is a longitudinal section of on the line IIII of Fi 1.

As will be seen from 51c drawing, a frame 1 rotating bearings 2 receives its rotary movement from some outside source of energy (direct-coupled motor, flexible shafting, belt transmission, and the like) The rota frame 3 is adapted to carry the striking masses 3, 3 which are diametrically opposed and consist, the embodiment shown, of cythe same lindrical rollers having trunnions 4 for their mounting.

The trunnions 4 are adapted to slide in slots 5 provided in the forks of the arms of the frame 1.

Therunway- 6 is of such a predetermined sha that it lifts the striking masses 33 durlng counter-clockwise rotation of the frame 1 through the angle B 0 A and then imposes on them variouspaths of movements as they come successively into contact with the. anvil 7 on the end of the tool.

The shape of the runway is such that the striking masses, in their travel, never leave the runway, except during the short interval of theblow, i. e. during their displacement through the angle A O B.

It IS known that the trajectory of each striking mass, when free, is a definite one in space, independent of its weight and the angular velocity of its rotary frame.

Furthermore, it is to be noted that the transmission of live power from each mass to the tool is effected over a slight amount of radial travel of this tool.

It is-therefore essential that the bulk of the apparatus should be subject to no displacement with respect to the anvil 7, at the risk of the capacity being considerably reduced.

mass, i. e. the angle during which it moves away from the centre of rotation, the curvature of the runway, in this sector, will be At the moment of shock, the strikin mass involved will leave the runway, i. e. uring, travelthrough the angle A. O B.

In order to obtain a good eguflibr'ation,

. IfD O A is the angle of escapement of the of the free trajectory of the mass in trav'e1 lingthrough this angle.

()wing to this fact, there willbe no recoil action on the bulk of the apparatus, i. e. no

, strainon the operator, or injurious action to the efiiciency of the blow. a

The part of the runway comprised in the angle B O C will be of any suitable form, for connecting, without shock, the trajectory of the bass within the angle A O B to the trajectory which this mass must have within the angle C O 1). Y i

It sh'ould be pointed out that the equilibration of 'the rotaryhammer system thus formed is not absolute, but that the lack of equilibration, resulting from the fact that, with respect to the vertical plane traversing the axis of rotation, the striking mass or masses located at any moment nearest the anvil are always on 'a radius of gyration greater than that of the diametrically opposed mass or masses, has the effect of supplementing the effort made by the workman on the body of the hammer, for the purpose of maintaining contact with the work piece.

In order to prevent shocks from being produced in the rotary-hammers when contact is resumed of the striking masses with the runway, the latter, in the region which receive during the last ortionof its run. The mass continues to rol on this extremity the resistancfi of which will be calculated according to nee To prevent all injurious vibrations in the portion 8, it may be made to bear against bearing-blocks 9, which may corporate with the runway or be independent thereof.

The end of runway 8 in its resilient portion will of course not come in contact with the casing 10 enclosing the different elements of the hammer.

' It is evident that the flexible portion 8 of the runway may be corporate with the latter,

as shown "in the drawing, or may be inserted in the gear case in any suitable manner.

It will be understood that the method of carrying the invention into effect, which is shown in the accompanying drawing, is'only described by way of example and that modifications may be resorted to as regards the forms given tothe runway, the number of the striking masses (the minimum number of the latter being two) and their displacement on the rotary frame, which displacements may be effected either along a radius, or along a trajectory oblique with respect to a radius.

What I claim is:

1. A hammer comprising a rotatable frame, masses carried by said frame and slidable radially therein under centrifugal force, a runway against which said masses bear except during the striking period, an anvil, that part of the runway immediately beyond the tool head or anvil being resilient to cushion the contact of the striking masses therewith as they leave the said tool head or anvil, the

part of the runway surend of the resilient rounding the anvil.

2. A hammer comprising a rotary masscarrying frame comprising forked arms in which the masses can slide outwardly, an enclosing case,a tool head or anvil projecting inwardly through the. case into the path of said masses, and a runway shaped to control the radial movement of the masses throughout their path except just during the striking period and having the portion surrounding the anvil and the portion ust beyond the tool head or anvil res1lient, substantially as an for the purposes specified.

In testimony whereof he has signed his name tothis specification. GEORGES ERNEST WAGNER. 

